Metal carrier and manufacturing method of metal carrier

ABSTRACT

A metal carrier according to the present invention is produced by superposing a metal flat sheet and a metal corrugated sheet on each other and winding them. In a winding end when the corrugated sheet and the flat sheet are wound, a corrugation height of the corrugated sheet is gradually lowered.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2006-019107 filed on Jan. 12,2006, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a metal carrier and a manufacturingmethod thereof for cleaning exhaust gas discharged from an internalcombustion engine of an automobile and the like.

2. Description of Related Art

There has been a conventional cleaning apparatus having a metal carriertherein, such as one shown in FIG. 1. According to this conventionalcleaning apparatus, a corrugated sheet 101 a and a flat sheet 101 b ofstainless sheet material constitute a metal carrier 101 of a honeycombstructure, and the metal carrier 101 is press-fitted into a container102. According to this cleaning apparatus, the corrugated sheet 101 aand the flat sheet 101 b are diffused-bonded to each other, thecontainer 102 and the metal carrier 101 are brazed with each other andin this state, the catalyst is applied to the metal carrier 101.Diffusers 104 are welded to both ends of the container 102, and functionas an inlet and an outlet through which exhaust gas is introduced intoand out from a catalyst section (see Japanese Patent No. 2779516).

As shown in a front view of FIG. 2 and an enlarged view of relevantparts of FIG. 3, the metal carrier 101 of the honeycomb structure isformed in such a manner that the band-like corrugated sheet 101 a andthe flat sheet 101 b are superposed on each another, they are woundaround a core metal 105 in a form of a roll and in this state, a top ofthe corrugated sheet 101 a and the flat sheet 101 b are bonded to eachother so that exhaust gas flows through cells 106 surrounded by thecorrugated sheet 101 a and the flat sheet 101 b. In the state where theyare wound in the form of the roll, the metal carrier 101 is press-fittedinto the cylindrical container 102 as shown in FIG. 4.

In the metal carrier 101 formed by winding the corrugated sheet 101 aand the flat sheet 101 b are wound in the form of the roll, a step Hcorresponding to a corrugation height is generated at a winding end asshown in FIG. 2. Therefore, when the metal carrier 101 is press-fittedinto the cylindrical container 102, the metal carrier 101 is locallydeformed due to the step H of the winding end. This deformationpropagates toward the center of the metal carrier 101, the shape of thecell 106 of the metal carrier 101 becomes different from the designedshape and there is a problem that performance of the metal carrier isdeteriorated.

This problem occurs more clearly when the shape of the corrugated sheet101 a to be used is changed from a type B having a low corrugationheight fh shown in FIG. 5B to a type A having high corrugation height fhshown in FIG. 5A. In the corrugated sheet of type B, a ratio fh/fp ofcorrugation height fh and corrugation pitch fp is less than 1 (fh/fp<1).

In the corrugated sheet of type A, the ratio hf/fp of the corrugationheight fh and the corrugation pitch fp is equal to or higher than 1(fh/fp≧1).

As shown in FIGS. 6A and 6B, there is a known cleaning apparatus havinga ceramic carrier therein. According to this cleaning apparatus, aceramic carrier 111 of a honeycomb structure is inserted into acylindrical container 112 in a state where a shock absorbing material113 is attached and in this state, the container 112 is provided at itsopposite ends with tapered diffusers 114 and the ceramic carrier 111 isheld by the spinning rollers SP. In this case, the ceramic carrier 111to be handled is of substantially circular, and there is no step at thewinding end unlike the metal carrier 101. Therefore, the shock absorbingmaterial 113 has a constant thickness (see Japanese Patent ApplicationLaid-open No. 2004-36398).

SUMMARY OF THE INVENTION

According to the metal carrier 101 proposed in Japanese Patent No.2779516, as described above, the cell shape is locally deformed when themetal carrier 101 is press-fitted into the cylindrical container 102 dueto the step H in the winding end, this deformation propagates toward thecenter, the shape of the metal carrier 101 becomes different from thedesigned shape, and there is a problem that this deteriorates theperformance.

When the shock absorbing material 113 having the constant thickness isused for holding the metal carrier like the ceramic carrier 111 of thehoneycomb structure proposed in Japanese Patent Application Laid-openNo. 2004-36398, the shock absorbing material 113 cannot absorb the stepH of the winding end, the holding force of the carrier is not stabilizedand thus, there is a problem that the metal carrier may fall out.Further, since the shock absorbing material 113 is required as anadditional member, this increases the cost.

It is an object of the present invention to provide a metal carrier anda manufacturing method thereof in which a step in a winding end of themetal carrier is eliminated and even when the metal carrier ispress-fitted into the container, the cell shape is not locally deformed.

To achieve the above object, the present invention provides a metalcarrier produced by superposing a metal flat sheet and a metalcorrugated sheet on each other and winding them, wherein a corrugationheight of the corrugated sheet is gradually lowered in a winding endwhen the flat sheet and the corrugated sheet are wound.

The present invention also provides a manufacturing method of a metalcarrier produced by superposing a metal flat sheet and a metalcorrugated sheet on each other and winding them, wherein in a windingend when the flat sheet and the corrugated sheet are wound, tops ofcorrugations of the corrugated sheet are sandwiched and fixed from amountain side and a valley side, machining is performed such that aninterval between the fixed tops of the corrugations is graduallywidened, thereby gradually lowering a corrugation height of thecorrugated sheet, the machined corrugated sheet and the flat sheet arewound, thereby producing the metal carrier.

Further, the present invention also provides a manufacturing method of ametal carrier produced by superposing a metal flat sheet and a metalcorrugated sheet on each other and winding them, wherein in a windingend when the flat sheet and the corrugated sheet are wound, machining isperformed such that tops of corrugations of the corrugated sheet arepushed, one by one, into grooves formed such that interval therebetweenis gradually widened, thereby gradually lowering a corrugation height ofthe corrugated sheet, the machined corrugated sheet and the flat sheetare wound, thereby producing the metal carrier.

Further, the present invention also provides a manufacturing method of ametal carrier produced by superposing a metal flat sheet and a metalcorrugated sheet on each other and winding them, wherein in a windingend when the flat sheet and the corrugated sheet are wound, pins areinserted into valleys of corrugations of the corrugated sheet from bothsides of the corrugated sheet, machining is performed such that aninterval between the inserted pins is gradually widened, therebygradually lowering a corrugation height of the corrugated sheet, andafter the machined corrugated sheet is subjected to press machining, thepress machined corrugated sheet and the flat sheet are wound, therebyproducing the metal carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a structure of a cleaning apparatusincorporated in a conventional metal carrier;

FIG. 2 is a sectional view showing a structure of the conventional metalcarrier;

FIG. 3 is an enlarged view of relevant parts in FIG. 17;

FIG. 4 is a sectional view showing a state where the metal carrier shownin FIG. 17 is to be press-fitted into the container;

FIGS. 5A and 5B are enlarged views showing types of corrugations ofcorrugated sheet constituting the metal carrier; and

FIGS. 6 are diagrams showing a structure of the cleaning apparatusincorporated in a conventional ceramic carrier, where 6A is a sidesectional view, and 6B is a transverse sectional view.

FIG. 7 is a perspective view showing a structure of a metal carrieraccording to a first embodiment of the present invention;

FIG. 8 is an explanatory diagram of a shape of a corrugated sheet in awinding end of the metal carrier according to the first embodiment;

FIG. 9 is an explanatory diagram of a problem of a normal pressmachining;

FIGS. 10A-10C are explanatory diagrams of a relationship between acorrugation pitch and a corrugation height;

FIG. 11 is a side view showing a structure of a machining apparatus ofthe metal carrier according to the first embodiment;

FIG. 12 is a side view showing a state where a machining operation inthe machining apparatus of the metal carrier according to the firstembodiment is completed;

FIG. 13 is a side view showing a structure of a machining apparatus of ametal carrier according to a second embodiment of the present invention;

FIG. 14 is a side view showing a state where the machining operation inthe machining apparatus of the metal carrier according to the secondembodiment is being performed;

FIG. 15 is another side view showing a state where the machiningoperation in the machining apparatus of the metal carrier according tothe second embodiment is being performed;

FIG. 16 is a side view showing a state where the machining operation inthe machining apparatus of the metal carrier according to the secondembodiment is completed;

FIG. 17 is a front view showing a structure of a machining apparatus ofa metal carrier according to a third embodiment of the presentinvention;

FIG. 18 is a plan view showing a structure of the machining apparatus ofthe metal carrier according to the third embodiment;

FIG. 19 is a side view showing a structure of the machining apparatus ofthe metal carrier according to the third embodiment;

FIG. 20 is a plan view showing a state where the machining operation inthe machining apparatus of the metal carrier according to the thirdembodiment is being performed;

FIG. 21 is a side view for explaining a press machining in the machiningapparatus of the metal carrier according to the third embodiment;

DETAILED DESCRIPTION OF EMBODIMENTS

A first embodiment of the present invention will be explained below withreference to the accompanying drawings. FIG. 7 is a perspective viewshowing a structure of a metal carrier according to the firstembodiment.

As shown in FIG. 7, a metal carrier 1 according to the first embodimentis formed in such a manner that a metal band-like corrugated sheet 2 anda flat sheet 3 are superposed on each other, and they are spirallywound. A braze sheet material is wound around an outer peripherythereof, and this is press-fitted into a container 4 that is made ofmetal, and this is heated in a vacuum state. With this structure, thecorrugated sheet 2 and the flat sheet 3 are diffused-bonded to eachother, the corrugated sheet 2 and the flat sheet 3 are brazed and bondedbetween the container 4, and the metal carrier 1 is formed.

The shape of the corrugated sheet 2 in the winding end of the metalcarrier 1 will be explained based on FIG. 8. As shown in FIG. 8, thecorrugation pitch of the corrugated sheet 2 having the corrugationheight of A is gradually widened, thereby lowering the corrugationheight to B. This corrugation height B is height from ⅓ to ¼ of thecorrugation height A. The length required for lowering the corrugationheight A to the corrugation height B is in a range of about ½ to 1/1 ofthe outer periphery of the metal carrier 1.

In the metal carrier 1 according to the first embodiment, in the windingend when the flat sheet 3 and the corrugated sheet 2 are wound, thecorrugation height of the corrugated sheet 2 is gradually lowered.Therefore, a step in the winding end can be eliminated. With thisstructure, the local deformation of the cell caused when it ispress-fitted into the container 4 can be prevented, and it is possibleto prevent the cleaning performance from being deteriorated. Since thecarrier holding force is stabilized, the metal carrier can be preventedfrom falling out. Further, since additional members such as a shockabsorbing material are unnecessary, it is possible to suppress theincrease in cost.

Next, a manufacturing method of the metal carrier according to the firstembodiment will be explained with reference to the accompanyingdrawings. Like the metal carrier 1 according to the present embodiment,as a machining method for gradually lowering the corrugation height inthe winding end of the corrugated sheet 2, it seems possible to employ apress machining. However, if attempt is made to gradually lower thecorrugation height of the corrugated sheet 2 by a normal pressmachining, as shown in FIG. 9, since shapes of an upper die 31, a lowerdie 32 and the corrugated sheet 2 are largely different from each otherand thus, the corrugated sheet 2 is deviated from the dies and isdeformed.

Hence, in this embodiment, as shown in FIGS. 10A-10 c, utilizing thefact that if the corrugation pitch is increased, the corrugation heightis reduced, the corrugation height in the winding end of the corrugatedsheet 2 is gradually lowered in the order of FIG. 10A, 10B, and 10C.

FIG. 11 shows a structure of a machining apparatus for graduallylowering the corrugation height of the corrugated sheet 2. As shown inFIG. 11, a machining apparatus 51 includes a plurality of dies 53 eachformed with a groove 52 for fixing a top of a corrugation of thecorrugated sheet 2, die retainer bolts 54 for connecting between thedies 53, punches 55 inserted into valleys of corrugations of thecorrugated sheet 2, punch holders 56 for holding the punches 55, punchretainer bolts 57 for connecting between the punch holders 56, and aslide base 58 for supporting the punch holders 56 such that the punchholders 56 can move laterally.

In the machining apparatus 51 having such a structure, FIG. 11 shows astate before machining, and the number of the dies 53 is equal to thenumber of mountains of the corrugated sheet 2. Each of the grooves 52 isformed in the upper surface of the die 53. The groove 52 has the sameR-size as that of the top of the corrugation of the corrugated sheet 2,and the dies 53 are connected to each other through the die retainerbolt 54.

Meanwhile, each the punch 55 is inserted into a hole (not shown) formedin the punch holder 56 and held therein, and the number of the punches55 and the number of punch holders 56 are equal to the number of valleysof the corrugated sheet 2. The punch holders 56 are connected to eachother through the punch retainer bolts 57, and are placed on the slidebase 58.

In the initial state shown in FIG. 11, the dies 53 and the punch holders56 are pushed in a winding direction by an actuator such as an airpressure cylinder and they come into intimate contact with each other.In this state, the width between the grooves 52 formed in the die 53 isthe same as a pitch of the mountains of the corrugated sheet 2. Theshape of the corrugated sheet 2 corresponds to the shape of the groove52 as shown in FIG. 11. Meanwhile, each punch 55 is held in a statewhere the punch 55 matches with a position of the valley of thecorrugated sheet 2.

If the punch 55 lowers in unison with the punch holder 56 and the slidebase 58, the punch 55 is inserted into the valley of the corrugatedsheet 2, and is fixed by sandwiching the top of the corrugation of thecorrugated sheet 2 between the die 53 and the groove 52.

If the punch holder 56 and the die 53 are then spread in synchronizationwith each other in the direction opposite from the winding direction byan actuator (not shown) such as an air pressure cylinder, as shown inFIG. 12, the corrugation height of the corrugated sheet 2 is graduallylowered, and the machining of the corrugated sheet 2 by the machiningapparatus 51 according to the present embodiment is completed.

At that time, an opening distance between the punch holder 56 and thedie 53 is preset by the punch retainer bolt 57 and the die retainer bolt54. Therefore, the corrugated sheet 2 is formed into a preset shape.

In the die retainer bolts 54 and the punch retainer bolts 57, fourthretainer bolts 54 and 57 from the left side are omitted in FIG. 11, andfifth retainer bolts are illustrated therein. This is because that thefifth and subsequent retainer bolts are longer than the dies, andretainer bolts extend over the right side dies as compared with theadjacent dies. Retainer bolts in this case are offset in a plandirection.

According to the manufacturing method of the metal carrier 1 of thefirst embodiment, in the winding end when the flat sheet 3 and thecorrugated sheet 2 are wound, the top of the corrugation of thecorrugated sheet 2 is sandwiched between the mountain side and thevalley side and fixed therebetween, they are spread such that theinterval between the fixed tops of the corrugations is graduallyincreased and the corrugation height of the corrugated sheet 2 isgradually lowered. Therefore, the step in the winding end of theproduced metal carrier 1 can be eliminated. Particularly in the presentembodiment, since the top of the corrugation of the corrugated sheet 2is sandwiched between the mountain side and the valley side and fixed,it is possible to perform the machining operation in a state where theshape of the corrugated sheet 2 is stabilized.

Next, a manufacturing method of a metal carrier according to a secondembodiment of the present invention will be explained with reference tothe accompanying drawings. FIG. 13 shows a structure of a machiningapparatus for gradually lowering the corrugation height of thecorrugated sheet 2. As shown in FIG. 13, the machining apparatus 71includes a die 73 formed with grooves 72 a to 72 g for fixing tops ofcorrugations of the corrugated sheet 2, and punches 74 a to 74 g to beinserted into valleys of the corrugations of the corrugated sheet 2. Asa mechanism for lowering the punches 74 a to 74 g, a general method suchas a method using a cam mechanism and a method using an actuator can beemployed.

In the machining apparatus 71 having such a structure, FIG. 13 shows astate before machining. The number of grooves 72 a to 72 g formed in thedie 73 is equal to the number of mountains of the corrugated sheet 2 atpositions of a machining-completion state.

Meanwhile, the shapes of the punches 74 a to 74 g correspond tospreading angles of the corrugated sheet 2. Positions of the punches 74a to 74 g correspond to the grooves 72 a to 72 g.

In the initial state shown in FIG. 13, the top of the corrugation of thecorrugated sheet 2 is set at the position of the groove 72 a. In thisstate, only the position of the groove 72 a matches the position of thetop of the corrugated sheet 2 and the position of the groove 72, and thecorrugated sheet 2 is placed on the die 73.

First, as shown in FIG. 14, only the punch 74 a is lowered, the top ofthe corrugation of the corrugated sheet 2 is sandwiched between thegroove 72 a to spread the first mountain. With this machining, theposition of the corrugated sheet 2 is deviated rightward in FIG. 14, andthe second mountain of the corrugated sheet 2 enters the groove 72 b.

Thereafter, as shown in FIG. 15, if the second punch 74 b is lowered tospread the second mountain of the corrugated sheet 2, the corrugatedsheet 2 further moves rightward. The punches from 74 c to 74 g arelowered in this order and the corrugated sheet 2 is pushed and spreadand finally, as shown in FIG. 16, all of the punches 74 a to 74 g arelowered the corrugated sheet 2 is pushed and spread to the preset state.With this structure, the corrugation height is gradually lowered, andthe machining of the corrugated sheet 2 by the machining apparatus 71according to the second embodiment is completed.

In the manufacturing method of the metal carrier according to the secondembodiment, in the winding end when the flat sheet 3 and the corrugatedsheet 2 are wound, the tops of the corrugations of the corrugated sheet2 are pushed, one by one, into the grooves 72 a to 72 g formed such thatthe interval is gradually widened so that the corrugation height of thecorrugated sheet 2 is gradually lowered. Therefore, the step in thewinding end of the produced metal carrier 1 can be eliminated.Particularly in the present embodiment, since a mechanism for moving thepunches 74 a to 74 g and the grooves 72 a to 72 g is unnecessary, theapparatus cost can be reduced.

Next, a manufacturing method of a metal carrier of a third embodiment ofthe present will be explained with reference to on the accompanyingdrawings. FIGS. 17 to 19 show a structure of a machining apparatus forgradually lowering the corrugation height of the corrugated sheet 2,wherein FIG. 17 is a front view, FIG. 18 is a plan view as viewed fromabove, and FIG. 19 is a side view showing a corrugated sheet of a statewherein it is set in the machining apparatus.

As shown in FIGS. 17 and 18, the machining apparatus 81 includes a die82 formed with a shape of the completed (spring biasing forceconsidered) corrugated sheet 2, lifters 83 on which the corrugated sheet2 is placed, pins 84 to be inserted into valleys of corrugations of thecorrugated sheet 2, pins 84 to be inserted into valleys of corrugationsof the corrugated sheet 2, blocks 85 for holding the pins 84, retainerbolts 86 for connecting the blocks 85, springs 87 for biasing the blocks85, and punches 88 formed with the shape of the completed corrugatedsheet 2.

In the machining apparatus 81 having such a structure, the corrugatedsheet 2 is placed on the lifters 83 placed on the die 82 beforemachining. The punches 88 are disposed above the die 82, and the die 82and the punches 88 are formed with shapes which can be obtained when themachining is completed. The pins 84 are held on the opposite sides ofthe corrugated sheet 2 by the blocks 85 and the springs 87. The numberof the pins 84 is equal to the number of mountains of corrugations to bemachined as shown in FIG. 12. The blocks 85 are connected through theretainer bolts 86.

In the initial state shown in FIG. 17, initial positioning of thecorrugated sheet 2 is performed on the lifter 83. Next, as shown in FIG.18, the pin 84 is pushed out in the direction of the arrow (1) againstthe biasing force of the spring 87 by an actuator such as an airpressure cylinder (not shown), and the pin 84 is inserted into thevalley of the corrugated sheet 2. Similarly, the other pin 84 is alsoinserted into the valley of the corrugated sheet 2. At that time, therelationship between the corrugated sheet 2 and the pins 84 is as shownin FIG. 19.

The block 85 is then moved in the direction of the arrow (2). If themovement is completed, the state shown in FIG. 20 is obtained. At thattime, as shown in FIG. 20, since the interval of the block 85 opened bythe retainer bolt 86 is previously set, the corrugated sheet 2 iswidened into a preset shape.

Next, the lifter 83 and the pin 84 are brought into standby states, thedie 82 is moved upward and the punch 88 is moved downward as shown inFIG. 21, the corrugated sheet 2 is subjected to the press-machining bythe molding shape between the die 82 an the punch 88, and the machiningof the corrugated sheet 2 by the machining apparatus 81 according to thepresent embodiment is completed.

In the manufacturing method of the metal carrier 1 according to thethird embodiment, in the winding end when the flat sheet 3 and thecorrugated sheet 2 are wound, the pins 84 are inserted from both sidesof the corrugated sheet 2 toward the valleys of the corrugation of thecorrugated sheet 2, the corrugated sheet 2 is widened so that theinterval between the inserted pins 84 is gradually widened, and themachining is performed such that the corrugation height of thecorrugated sheet 2 is gradually lowered. Therefore, the step in thewinding end of the produced metal carrier 1 can be eliminated.Particularly in the present embodiment, the pins 84 are inserted intothe valleys of the corrugation of the corrugated sheet 2 from both sidesof the corrugated sheet 2, the corrugated sheet 2 is widened so that theinterval of the inserted pins 84 is gradually widened and then, thepress machining is additionally performed. Therefore, the shape of thecorrugated sheet 2 can precisely be formed.

Although the metal carrier and the manufacturing method thereof of thepresent invention have been explained based on the exemplaryembodiments, the present invention is not limited to the embodiments,and the structure of each portion can be replaced by an arbitrarystructure having like functions.

According to the metal carrier of the present invention, the corrugationheight of the corrugated sheet is gradually lowered in the winding endwhen the flat sheet and the corrugated sheet are wound. Therefore, thestep in the winding end can be eliminated, and the local deformation ofthe cell shape which occurs when the cell is press-fitted into thecontainer can be prevented, and it is possible to prevent the cleaningperformance from being deteriorated.

According to the manufacturing method of the metal carrier of thepresent invention, in a winding end when the flat sheet and thecorrugated sheet are wound, tops of corrugations of the corrugated sheetare sandwiched and fixed from a mountain side and a valley side,machining is performed such that an interval between the fixed tops ofthe corrugations is gradually widened, thereby gradually lowering acorrugation height of the corrugated sheet. Therefore, the step in thewinding end of the produced metal carrier can be eliminated.Particularly, since the tops of corrugations of the corrugated sheet aresandwiched from the mountain side and the valley side and fixedtherebetween, the machining can be performed in a state where the shapeof the corrugated sheet is stabilized.

According to the manufacturing method of the metal carrier of thepresent invention, in a winding end when the flat sheet and thecorrugated sheet are wound, machining is performed such that tops ofcorrugations of the corrugated sheet are pushed, one by one, intogrooves formed such that interval therebetween is gradually widened,thereby gradually lowering a corrugation height of the corrugated sheet.Therefore, the step in the winding end of the produced metal carrier canbe eliminated. Particularly, since a mechanism for moving the groove isunnecessary, it is possible to reduce the apparatus cost.

According to the manufacturing method of the metal carrier of thepresent invention, in a winding end when the flat sheet and thecorrugated sheet are wound, pins are inserted into valleys ofcorrugations of the corrugated sheet from both sides of the corrugatedsheet, machining is performed such that an interval between the insertedpins is gradually widened, thereby gradually lowering a corrugationheight of the corrugated sheet, and after the machined corrugated sheetis subjected to press machining, the press machined corrugated sheet andthe flat sheet are wound. Therefore, the step in the winding end of theproduced metal carrier can be eliminated. Particularly, the pins areinserted into the valleys of the corrugations of the corrugated sheetfrom both sides of the corrugated sheet, the interval between theinserted pins is widened such that it is gradually widened and then, thepress machining is additionally performed. Thus, it is possible toprecisely machine the shape of the corrugated sheet.

Although the invention has been described above by reference to certainembodiments of the invention, the invention is not limited to theembodiments described above. Modifications and variations of theembodiments described above will occur to those skilled in the art, inlight of the teachings. The scope of the invention is defined withreference to the following claims.

1. A metal carrier produced by superposing a metal flat sheet and ametal corrugated sheet on each other and winding them, wherein acorrugation height of the corrugated sheet is gradually lowered in awinding end when the flat sheet and the corrugated sheet are wound.
 2. Amanufacturing method of a metal carrier produced by superposing a metalflat sheet and a metal corrugated sheet on each other and winding them,wherein in a winding end when the flat sheet and the corrugated sheetare wound, tops of corrugations of the corrugated sheet are sandwichedand fixed from a mountain side and a valley side, machining is performedsuch that an interval between the fixed tops of the corrugations isgradually widened, thereby gradually lowering a corrugation height ofthe corrugated sheet, the machined corrugated sheet and flat sheet arewound, thereby producing the metal carrier.
 3. A manufacturing method ofa metal carrier produced by superposing a metal flat sheet and a metalcorrugated sheet on each other and winding them, wherein in a windingend when the flat sheet and the corrugated sheet are wound, machining isperformed such that tops of corrugations of the corrugated sheet arepushed, one by one, into grooves formed such that interval therebetweenis gradually widened, thereby gradually lowering a corrugation height ofthe corrugated sheet, the machined corrugated sheet and flat sheet arewound, thereby producing the metal carrier.
 4. A manufacturing method ofa metal carrier produced by superposing a metal flat sheet and a metalcorrugated sheet on each other and winding them, wherein in a windingend when the flat sheet and the corrugated sheet are wound, pins areinserted into valleys of corrugations of the corrugated sheet from bothsides of the corrugated sheet, machining is performed such that aninterval between the inserted pins is gradually widened, therebygradually lowering a corrugation height of the corrugated sheet, andafter the machined corrugated sheet is subjected to press machining, thepress machined corrugated sheet and flat sheet are wound, therebyproducing the metal carrier.